Suddenly my Centrals got a lot more disruptive

[Sleeprider]

Stomach sleeping (prone) can cause positional apnea as you will turn your head to the side. I can't sleep in that position as i become more congested and obstructed, but if you like it, watch for clusters of obstructive apnea or increases on flow limitation. The chart you quoted above had a 95% flow limitation of 0.10 and the current night is 0.12. That is what I meant by "sustained" flow limitation in spite of your EPR of 3.

There is no doubt you have mixed central and obstructive apnea, but the CAI is below the level at which ASV will be prescribed. I will add that if you did have ASV, your event rate would be essentially zero and the periodic breathing would be resolved. The only difference between the Vauto and CPAP is the availability of more pressure support to improve ventilation, and some settings for inspiration time and trigger/cycle sensitivity. Your CPAP is a simplified bilevel with pressure support limited to 3. There is no other difference between the delivery of EPR and the deliver of PS in the Vauto. "Oxygenation" is not a term we normally use with either CPAP or the Vauto. As long as respiration is maintained, oxygen is usually not a problem. With bilevel we can use a higher EPAP pressure to maintain a higher positive end expiratory pressure (PEEP) which is used in ventilation to improve oxygen perfusion and recruit lung volume, but I would consider that a special case we have not discussed as pertinent to you.

[tcinoz]

Thanks Sleeprider. I appreciate your analysis and am still learning to make sense of it all, gradually improving my understanding of what's going on.

Out of interest, can the ASV machine be set to do all the things the Vauto and the Airsense 11 are able to do, and then some? What I'm wondering is whether your recommendation for the Vauto over the ASV is based on price and whether I'd qualify, or does the Vauto do things the ASV can't which would address my symptoms even better than the ASV? Your assessment that an ASV would eliminate my AHIs altogether is certainly tempting, especially after last night.

Not a bad start - the reading was 2.7 per hour after my first stretch of sleep, but it went south rapidly in the later hours. The rate of AHIs was as bad as during my initial sleep study in parts.

I might try again with a fixed setting of 12 or 13 tonight with comfort level 2, just to see what happens if I conform with what the titration study recommended before I see my sleep doctor for the follow-up appointment next Monday. (Previously that pressure level seemed uncomfoftably high at the outset.)


         

[Sleeprider]

ASV is perhaps the better choice if you can do it. You would certainly eliminate nearly all events. I wish we had unlimited ability to trial therapy alternatives. The main difference with ASV vs Vauto is that you will get ASV mode, not bilevel mode, which means variable pressure support on a breath by breath basis. This is very effective, but can also be more disruptive; however you will never have a central event again, even if we raise minimum pressure support high enough to kill off those flow limits. ASV is a safe choice for problems like you're having, but it is more expensive and harder to authorize. There are ways around it. I don't like to see ASV used unnecessarily, but your therapy profile is one that likely benefits from it. Thanks for reading between the lines.

[stevew168]

The number and density of central apneas later in the night, likely associated with REM sleep, is concerning even though your overall AHI is not too high. It would be useful to know your SpO2 reading, especially later in the night.

[tcinoz]

ASV is perhaps the better choice if you can do it. You would certainly eliminate nearly all events.  I wish we had unlimited ability to trial therapy alternatives.  The main difference with ASV vs Vauto is that you will get ASV mode, not bilevel mode, which means variable pressure support on a breath by breath basis. This is very effective, but can also be more disruptive; however you will never have a central event again, even if we raise minimum pressure support high enough to kill off those flow limits.  ASV is a safe choice for problems like you're having, but it is more expensive and harder to authorize.  There are ways around it.   I don't like to see ASV used unnecessarily, but your therapy profile is one that likely benefits from it.  Thanks for reading between the lines.

Thanks again - I'll bear that in mind. It's been a struggle to get things right with the Airsense 11 but I'm told that as long a my AHI is under 5 it's doing its job. I know how I feel most mornings and think there's plenty of room for improvement. I'll put all this to my sleep doctor on Monday.

[tcinoz]

The number and density of central apneas later in the night, likely associated with REM sleep, is concerning even though your overall AHI is not too high. It would be useful to know your SpO2 reading, especially later in the night.

You're right, I need to get an O2 monitor, but I've held off, thinking it could just cause extra stress.

When I had the titration study I asked in the morning if O2 was a problem and was told no, but the fact is I was in a deep sleep when I was woken only five hours after dropping off, and those CAs I experience in clusters usually manifest in the final two or three hours of a full night's sleep.

[Sleeprider]

I didn't mention that we use the trigger sensitivity feature on the Vauto to improve results with centrals. It's not perfect, and it's certainly unknown amongst the medical community, but high or very-high trigger sensitivity will trigger IPAP pressure support with minimal inspiratory flow. Most people with therapy onset and apneic threshold CA will continue to move a small amount of air as a central apnea initiates. Typical central apnea onsets with gradually diminished spontaneous respiration effort, not a sudden lock of flow like we see in OSA. A high or very high IPAP trigger sensitivity will often stimulate a spontaneous breath as the pressure support is sensed. It is not capable of causing a breath, but it can stimulate it. We even use low ASV pressure support settings to do the same thing in individuals using that therapy, but with intolerance to high pressure support. If pressure support is triggered, a normal breath often results in places where a CA event might otherwise occur. Fair warning, your doctor does not know this, and it is not claimed as a feature by the VPAP manufacturers, but since we have to "kludge" therapy for many individuals affected by mild and moderate central apnea here, we have learned this and demonstrated it in many many cases. If you want some sense of the scope of the success of this tactic, do a Google search: "high trigger sensitivity Site:Apneaboard.com"

[stevew168]

You are so right, Sleeprider. Here is an example from my ASV with OSCAR, if what you are referring to. Its not quite an apnea, but the ASV get's the respiration started again.

[Sleeprider]

Your ASV provided IPAP pulses where respiratory flow stopped and changed to higher PS as the minute vent fell at 07:03:40+. This is the backup breath, and in this case, the breathing pause was an inspiratory breath-hold (no expiration flow until 07:03:45). As a result there was no positive flow rate response to the IPAP pulse. We see a similar response with the Vauto on very-high trigger, but it only works for a real central event, not arousals with movements or breath-holds like the example posted by stevew168

[tcinoz]

I didn't mention that we use the trigger sensitivity feature on the Vauto to improve results with centrals.  It's not perfect, and it's certainly unknown amongst the medical community, but high or very-high trigger sensitivity will trigger IPAP pressure support with minimal inspiratory flow. Most people with therapy onset and apneic threshold CA will continue to move a small amount of air as a central apnea initiates.  Typical central apnea onsets with gradually diminished spontaneous respiration effort, not a sudden lock of flow like we see in OSA.  A high or very high IPAP trigger sensitivity will often stimulate a spontaneous breath as the pressure support is sensed.  It is not capable of causing a breath, but it can stimulate it. We even use low ASV pressure support settings to do the same thing in individuals using that therapy, but with intolerance to high pressure support. If pressure support is triggered, a normal breath often results in places where a CA event might otherwise occur.  Fair warning, your doctor does not know this, and it is not claimed as a feature by the VPAP manufacturers, but since we have to "kludge" therapy for many individuals affected by mild and moderate central apnea here, we have learned this and demonstrated it in many many cases.  If you want some sense of the scope of the success of this tactic, do a Google search: "high trigger sensitivity Site:Apneaboard.com"

Thanks again, Sleeprider. I can't pretend to fully understand everything you describe, but I follow the broad gist of it. I can see I'll have to get down among the weeds and do some more background reading on exactly what goes on with these processes.

For now, my immediate concern after a terrible night where the last couple of hours were spent with an event every minute or so is getting another gadget to monitor my heart-rate (for a second opinion), as my pulse oximeter was reading dips into the 20s on several occasions when my breathing slowed to a stop. Alarming to say the least, although of course it would pick up again pretty quickly. 90% was the lowest O2 level I observed. This was after a relatively reasonable night till about 5 am spent lying down, with the AHI reading at 2.1. I then couldn't sleep any more lying down so I got up for a while, during which time I read my SD card on Oscar on my laptop. Then I set up my recliner and changed mask to an F30i and could hear the whoosh every time my breathing failed (and checked the reading every so often on my oximeter which I'd left switched on on my finger.)  I did catch enough sleep in snatches to get up a couple of hours later, but by then the readout on my Resmed Airsense 11 had jumped from 2.1 p/h to 7.2 p/h - presumably averaged out over the whole night. On getting up I took the SD card out again and inserted into my laptop, but this last part of my sleep with the crucial information about what was my worst period of sleep with the macine to date was totally missing!! Any idea why this could have happened?